Yielding chuck for taps and drills.



W.. WIIIMMIIWWEEEE N I L d@ W. L. 1PROGUNIERn YIBLDING CHUCK FOR TAPS AND DRILLS.

APPLICATION FILED HOV. 30. 1906.

'WILLIAM L. PROCUNIER, OF CHICAGO, ILLINOIS.

YIELDING CHUCK FOR TAPS ANI) DBILLS.

To all whom 'it may concern.'

Be it known that I, WILLIAML. PROCUNIER, a citizen of the United States, residing at Chicago, in the county of Cook and ,St/ate of Illinois, have invented new' and useful Improvements in Yielding Chucks for Taps and Drills, of which the following is a specification, reference being had to the accompanying drawings, forming a part thereof.

The purpose of this invention is to provide an improved chuck, particularly adapted for holdingscrew taps, adapted to hold such taps sufficiently for driving them to their work, but to yield their grasp or permit the tap to slip in the chuck when it reaches the bottom of the hole which is being tapped or encounters any other obstruction to its movement which would cause it to break if driven positively. The sameexpediente adapt the chuck for holding a drill so that the grasp of the chuck on the drill may yield when the resistance approaches too nearly the strength of the tool to make it safe to drive positively.

. The improvement consists in thel expedients for gripping the tool-yieldingly and in the employment of a spring to effect such yielding grip. It consists also of the specific features of construction for accomplishing the result stated, which will be under-stood from the specification and which are set out in the specific claims. p

In the drawingsr--Figure l is an axial section of the chuck embodying my invention showing a tool therein. Fig. 2 is a section at the line 2-2 on Fig.I l. Fig. 3 is a view similar to Fig. l showing a modification of the device. Fig. 4 is a section at the line 4-4 on Fig. 2.

In the form of my invention shown 'inFigs land 2, the stem or shank, l, of the tool to beheld is engaged between the two halves, 2-` 2, of a gripper, the axle bore of which, consisting of matched grooves in the two' halves, seats the toolshank. This gripper is preferably tapered as shown, and it has an annular boss, 3,'

extending around it half upon each of the two halves of the gripper. 4 is an interiorly conical sleevewithin which the two-part gripper, 2, 2, islodged, the boss, 3, seating upon the conical wall of said sleeve so that any pressure tending to thrust the gripper longitudinally in the sleeve, l, the smaller end thereof causes the two halves to be crowded together and to grip the tool.' shank firmly. 5 is the 'exterior shell of the chuck.,

-The interiorly Vconical sleeve, 4, is accurately telescoped within it. Two pins, 6, '6, project from the upper end of the cavity of the shell and take respectively into the'two members, 2, 2, of the gripper for driving the latter by the rotation of vthe shell. The shank or stem of the chuck, 7, projects integrally from the upper end'of the shell Aand is provided in the customary manner for holding it in another chuck or driving head of a drill press' or athe. .'The tool for.con venience'mayA be provided at the upper end of its speeineation of Letters Patent; Application filed November 30, 196. Serial No. 345,622.

Patented uly 16, 1907.

.shank with a flange, l, by which it hangs from the up- K l invention. The two-part gripper is stopped at the upper end by the shell, and the'interiorly conical sleeve, 4, is pressed upward to force the two parts of the gripper together, by means of a spring, 8, at the lower end of the sleeve stopped there-against and retained and compressed for any desired tension by means of the cap,

10, which is screwed on to the shell at theilower ,end of the latter, being centrally apertured for the tool. The

amount of `grip which thedevice shall have upon the tool is determined by the tension given the spring by screwing up the cap more or less.

It will he seen that the squared upper end of the twopart gripper seating against the similarly squared upper end of the cavity of the shell, 5, operates to fix the axis of the' sat for the tool shank and thereby to fix the tool in true position axially with respelct to the entire chuck. The purpose of. the encompassing annular boss, 3, is to cause the pressure 'for closing up the gripper parts to be applied in such manner that the tool shank may be gripped the entire length of the gripper,

even though the shank be slightly tapered, and to pre-V vent the grip from being limited to a mere line at one end or the other of the gripper, as might be the case if the two elements of the gripper were notato a limited extent free to accommodate themselves to the tool shank by rocking, if necessary, at the seat of the boss on the interiorly conical sleeve. It will be obvious that to such slight extent as might be caused by a taper or inequality in the diameter of the tool shank, such accommodation ofthe gripper parts to the tool shankl may prevent their squared upper ends y,from seating the cavity in the shell, but the result would still be to squarely on the correspondingly squared upper end of a hold the tool substantially axial with respect to the chuck. Preferably, in order''that the possibility of variation from axial position 'may be slight, and yet su'chasto permit the tool to accommodate itself slightly to the work, I prefer to make the two-part gripper exteriorly conical, conforming substantially and as accurately as possible to the conical taper of the interior vwall of the sleeve while retaining the bow described projecting from such conical surface so. that it constitutes the actual seat of the one part upon the other in the crowding action for gripping the tool; and any cause tending to defeat the perfectly axial position of ther tool can at most only tip it'to' the extent of the clearance between two conical surfacesfthe outer surface of the two-part gripper and the inner surface of the sleeve.

It will be understood that the boss might be omitted and the result obtained solely by the coperation of the two conical surfaces seating one upon the other; but in that case, if they should not have absolutely the saine taper, or if the tool shank should beslightly tapered,

and the grooves of the gripp'er were not conformed to such taper the grip upon the tool would be liable toV be coniinedvto a single line at one end'or the other of the gripper. y

In the form shown in Figs. 3 and 4, the twopart gripper is dispensed with, and instead I provide a conical holder, 9, axially bored to receive the shank of the tool, and at the upper end of the bore the same `reduced and squared to receive the squared upper end' of the shank for. rotating the tool.V This holder amounts to an enlargement of the shankduring its use in the chuck, since it isadapted to carry the toolv with it in all`its movements.A The sleeve, 4, is substantially the same'- in the other form, except that it `has lugs, 4, engaging slots,` 5,- in the shell, 5,-for drawing positively. Thef.sleeve,4,"is pressed upby the spring, 8, as in the other form, 'the tension of the spring being governed by the adjnstment'oi thefcap as in the other form. *Inv the first form,v when the resistance to the tool 4becomes too great, its shank 4willslip ein the two." par gripperwhereat the is determined by thetension of thespring pressing the gripper elements up and so crowding them together by reasonl of thetaper of the`v sleeve into which they are thus pressed; In th'e second form, when the resistance becomes too-great forthe safety of the tool, the conical holder, 9,;will slip at its seat in the interiorly conical sleeve which ispressed up against it by the spring.

1. A tool-holding chuck comprising an outer sh'ell: au lnterorly conical sleeve within the shell; an axially apertnredholder for the-tool shank within the sleeve exteriorly formed for seating on the interior conical surface -ot the sleeve; a spring which presses the slee'velongitudinaily onto the holder, and a sto'por the spring mounted-n 'the'- shell. f

2. A tool-hoidingchuck comprising an outerheli; an interiorly conical sleeve within the shell an axially apertu'red holder tor the tool 'shank within the sleeve exterioriy formed for seating on the interiorlylconical surface'ot the sleeve; a spring4 whichrpresses upon -the outerend of the'l 'split hoder for gripping the sleeve for forcing it onto the holder, and a centrally apertured screw cap having a central aperture for the tool screwed onto' the shell for stopping the spring.

-3. A tool-holding chuck comprising an outer shell: an interiorly conical sleeve within the shell; a. two-part or longitudinally split holder for the tool shank within the sleeve extcriorly formed for seating on the iuterioriy conical surface of the sleeve; a spring within the shell pressing upon the outer end ot the sleeve for forcing it onto the split holder, and a centrally apertured threaded closure for the shell for stopping the spring.

4. A tool-holding chuck comprising an outer shell.; interiorly conical sleeve within the shell; an axially apertured holder for the tool ,shank within the sleeve. such hoiderheing longitudinally spllt'and exterior-ly formed tor seating on the interlorly conical` surface of the sleeve; means engaging theupper or inner ends of the'two split parts of the split holder with the shell for-rotation; a spring in the shell pressing upon the lower end of the sleeve for forcing it yieldingl up onto the split holder -for crowding its two parts toget er, and a centrally apertured closure for the end of the shell threaded for engagement therewith to retain the spring.

5.v A tool-holding chuck vcomprisinganA nui-er shell; ani

interiorly conical sleeve within the shell; a two-part or split holder for gripping the tool shank having an exterior annuiar'ho'ssiiltermediate its ends for seating on the interioriy conical surface of the sleeve; a spring within the shell pressing upon the lower end of the sleeve to force it yieldingly up onto the two-part holder, and a closure forAA the shell centrally apertured for the tool and threaded for engagement with the shell for retaining the spring.

6. A tool-holding chuck comprising an outer shell; an interiorly conical sleeve within the shell; a two-part or tool shank provided at the upper end with means engaging it with the shell for rotation, such gripper having an exterior annular boss for seating on the interioriy conical surface of the sleeve; n spring within the shell pressing upon the lower end of the sleeve for forcing it yieldingly up onto the holder, and a centrally apertured closure for the shell exterioriy threaded for engagement therewith for retaining the4 spring.

In'testimony whereof, I have hereunto set my hand at Chicago, Illinois; this 24th day of November, A. D., 1906.-

WILLIAM L. PROCUNIER.

Witnesses:

EDWARD-T. Waar,

J. S. Assor'r. 

